2 * FUSE: Filesystem in Userspace
3 * Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
5 * Helper functions to create (simple) standalone programs. With the
6 * aid of these functions it should be possible to create full FUSE
7 * file system by implementing nothing but the request handlers.
9 * This program can be distributed under the terms of the GNU LGPLv2.
10 * See the file COPYING.LIB.
13 #include "qemu/osdep.h"
15 #include "fuse_lowlevel.h"
16 #include "fuse_misc.h"
25 #include <sys/param.h>
27 #include <sys/resource.h>
30 #define FUSE_HELPER_OPT(t, p) \
32 t, offsetof(struct fuse_cmdline_opts, p), 1 \
34 #define FUSE_HELPER_OPT_VALUE(t, p, v) \
36 t, offsetof(struct fuse_cmdline_opts, p), v \
39 static const struct fuse_opt fuse_helper_opts
[] = {
40 FUSE_HELPER_OPT("-h", show_help
),
41 FUSE_HELPER_OPT("--help", show_help
),
42 FUSE_HELPER_OPT("-V", show_version
),
43 FUSE_HELPER_OPT("--version", show_version
),
44 FUSE_HELPER_OPT("--print-capabilities", print_capabilities
),
45 FUSE_HELPER_OPT("-d", debug
),
46 FUSE_HELPER_OPT("debug", debug
),
47 FUSE_HELPER_OPT("-d", foreground
),
48 FUSE_HELPER_OPT("debug", foreground
),
49 FUSE_OPT_KEY("-d", FUSE_OPT_KEY_KEEP
),
50 FUSE_OPT_KEY("debug", FUSE_OPT_KEY_KEEP
),
51 FUSE_HELPER_OPT("-f", foreground
),
52 FUSE_HELPER_OPT_VALUE("--daemonize", foreground
, 0),
53 FUSE_HELPER_OPT("fsname=", nodefault_subtype
),
54 FUSE_OPT_KEY("fsname=", FUSE_OPT_KEY_KEEP
),
55 FUSE_HELPER_OPT("subtype=", nodefault_subtype
),
56 FUSE_OPT_KEY("subtype=", FUSE_OPT_KEY_KEEP
),
57 FUSE_HELPER_OPT("max_idle_threads=%u", max_idle_threads
),
58 FUSE_HELPER_OPT("--rlimit-nofile=%lu", rlimit_nofile
),
59 FUSE_HELPER_OPT("--syslog", syslog
),
60 FUSE_HELPER_OPT_VALUE("log_level=debug", log_level
, FUSE_LOG_DEBUG
),
61 FUSE_HELPER_OPT_VALUE("log_level=info", log_level
, FUSE_LOG_INFO
),
62 FUSE_HELPER_OPT_VALUE("log_level=warn", log_level
, FUSE_LOG_WARNING
),
63 FUSE_HELPER_OPT_VALUE("log_level=err", log_level
, FUSE_LOG_ERR
),
67 struct fuse_conn_info_opts
{
69 int no_remote_posix_lock
;
78 int no_auto_inval_data
;
80 int no_readdirplus_auto
;
84 int no_writeback_cache
;
88 unsigned max_readahead
;
89 unsigned max_background
;
90 unsigned congestion_threshold
;
93 int set_max_readahead
;
94 int set_max_background
;
95 int set_congestion_threshold
;
99 #define CONN_OPTION(t, p, v) \
101 t, offsetof(struct fuse_conn_info_opts, p), v \
103 static const struct fuse_opt conn_info_opt_spec
[] = {
104 CONN_OPTION("max_write=%u", max_write
, 0),
105 CONN_OPTION("max_write=", set_max_write
, 1),
106 CONN_OPTION("max_readahead=%u", max_readahead
, 0),
107 CONN_OPTION("max_readahead=", set_max_readahead
, 1),
108 CONN_OPTION("max_background=%u", max_background
, 0),
109 CONN_OPTION("max_background=", set_max_background
, 1),
110 CONN_OPTION("congestion_threshold=%u", congestion_threshold
, 0),
111 CONN_OPTION("congestion_threshold=", set_congestion_threshold
, 1),
112 CONN_OPTION("sync_read", sync_read
, 1),
113 CONN_OPTION("async_read", async_read
, 1),
114 CONN_OPTION("atomic_o_trunc", atomic_o_trunc
, 1),
115 CONN_OPTION("no_remote_lock", no_remote_posix_lock
, 1),
116 CONN_OPTION("no_remote_lock", no_remote_flock
, 1),
117 CONN_OPTION("no_remote_flock", no_remote_flock
, 1),
118 CONN_OPTION("no_remote_posix_lock", no_remote_posix_lock
, 1),
119 CONN_OPTION("splice_write", splice_write
, 1),
120 CONN_OPTION("no_splice_write", no_splice_write
, 1),
121 CONN_OPTION("splice_move", splice_move
, 1),
122 CONN_OPTION("no_splice_move", no_splice_move
, 1),
123 CONN_OPTION("splice_read", splice_read
, 1),
124 CONN_OPTION("no_splice_read", no_splice_read
, 1),
125 CONN_OPTION("auto_inval_data", auto_inval_data
, 1),
126 CONN_OPTION("no_auto_inval_data", no_auto_inval_data
, 1),
127 CONN_OPTION("readdirplus=no", no_readdirplus
, 1),
128 CONN_OPTION("readdirplus=yes", no_readdirplus
, 0),
129 CONN_OPTION("readdirplus=yes", no_readdirplus_auto
, 1),
130 CONN_OPTION("readdirplus=auto", no_readdirplus
, 0),
131 CONN_OPTION("readdirplus=auto", no_readdirplus_auto
, 0),
132 CONN_OPTION("async_dio", async_dio
, 1),
133 CONN_OPTION("no_async_dio", no_async_dio
, 1),
134 CONN_OPTION("writeback_cache", writeback_cache
, 1),
135 CONN_OPTION("no_writeback_cache", no_writeback_cache
, 1),
136 CONN_OPTION("time_gran=%u", time_gran
, 0),
137 CONN_OPTION("time_gran=", set_time_gran
, 1),
142 void fuse_cmdline_help(void)
144 printf(" -h --help print help\n"
145 " -V --version print version\n"
146 " --print-capabilities print vhost-user.json\n"
147 " -d -o debug enable debug output (implies -f)\n"
148 " --syslog log to syslog (default stderr)\n"
149 " -f foreground operation\n"
150 " --daemonize run in background\n"
151 " -o cache=<mode> cache mode. could be one of \"auto, "
154 " -o flock|no_flock enable/disable flock\n"
155 " default: no_flock\n"
156 " -o log_level=<level> log level, default to \"info\"\n"
157 " level could be one of \"debug, "
158 "info, warn, err\"\n"
159 " -o max_idle_threads the maximum number of idle worker "
161 " allowed (default: 10)\n"
162 " -o posix_lock|no_posix_lock\n"
163 " enable/disable remote posix lock\n"
164 " default: no_posix_lock\n"
165 " -o readdirplus|no_readdirplus\n"
166 " enable/disable readirplus\n"
167 " default: readdirplus except with "
169 " -o sandbox=namespace|chroot\n"
170 " sandboxing mode:\n"
171 " - namespace: mount, pid, and net\n"
172 " namespaces with pivot_root(2)\n"
173 " into shared directory\n"
174 " - chroot: chroot(2) into shared\n"
175 " directory (use in containers)\n"
176 " default: namespace\n"
177 " -o timeout=<number> I/O timeout (seconds)\n"
178 " default: depends on cache= option.\n"
179 " -o writeback|no_writeback enable/disable writeback cache\n"
180 " default: no_writeback\n"
181 " -o xattr|no_xattr enable/disable xattr\n"
182 " default: no_xattr\n"
183 " -o modcaps=CAPLIST Modify the list of capabilities\n"
184 " e.g. -o modcaps=+sys_admin:-chown\n"
185 " --rlimit-nofile=<num> set maximum number of file descriptors\n"
186 " (0 leaves rlimit unchanged)\n"
187 " default: min(1000000, fs.file-max - 16384)\n"
188 " if the current rlimit is lower\n"
189 " -o allow_direct_io|no_allow_direct_io\n"
190 " retain/discard O_DIRECT flags passed down\n"
191 " to virtiofsd from guest applications.\n"
192 " default: no_allow_direct_io\n"
193 " -o announce_submounts Announce sub-mount points to the guest\n"
197 static int fuse_helper_opt_proc(void *data
, const char *arg
, int key
,
198 struct fuse_args
*outargs
)
204 case FUSE_OPT_KEY_NONOPT
:
205 fuse_log(FUSE_LOG_ERR
, "fuse: invalid argument `%s'\n", arg
);
209 /* Pass through unknown options */
214 static unsigned long get_default_rlimit_nofile(void)
216 g_autofree gchar
*file_max_str
= NULL
;
217 const rlim_t reserved_fds
= 16384; /* leave at least this many fds free */
218 rlim_t max_fds
= 1000000; /* our default RLIMIT_NOFILE target */
223 * Reduce max_fds below the system-wide maximum, if necessary. This
224 * ensures there are fds available for other processes so we don't
225 * cause resource exhaustion.
227 if (!g_file_get_contents("/proc/sys/fs/file-max", &file_max_str
,
229 fuse_log(FUSE_LOG_ERR
, "can't read /proc/sys/fs/file-max\n");
232 file_max
= g_ascii_strtoull(file_max_str
, NULL
, 10);
233 if (file_max
< 2 * reserved_fds
) {
234 fuse_log(FUSE_LOG_ERR
,
235 "The fs.file-max sysctl is too low (%lu) to allow a "
236 "reasonable number of open files.\n",
237 (unsigned long)file_max
);
240 max_fds
= MIN(file_max
- reserved_fds
, max_fds
);
242 if (getrlimit(RLIMIT_NOFILE
, &rlim
) < 0) {
243 fuse_log(FUSE_LOG_ERR
, "getrlimit(RLIMIT_NOFILE): %m\n");
247 if (rlim
.rlim_cur
>= max_fds
) {
248 return 0; /* we have more fds available than required! */
253 int fuse_parse_cmdline(struct fuse_args
*args
, struct fuse_cmdline_opts
*opts
)
255 memset(opts
, 0, sizeof(struct fuse_cmdline_opts
));
257 opts
->max_idle_threads
= 10;
258 opts
->rlimit_nofile
= get_default_rlimit_nofile();
259 opts
->foreground
= 1;
261 if (fuse_opt_parse(args
, opts
, fuse_helper_opts
, fuse_helper_opt_proc
) ==
270 int fuse_daemonize(int foreground
)
279 fuse_log(FUSE_LOG_ERR
, "fuse_daemonize: pipe: %s\n",
285 * demonize current process by forking it and killing the
286 * parent. This makes current process as a child of 'init'.
290 fuse_log(FUSE_LOG_ERR
, "fuse_daemonize: fork: %s\n",
296 _exit(read(waiter
[0], &completed
,
297 sizeof(completed
) != sizeof(completed
)));
300 if (setsid() == -1) {
301 fuse_log(FUSE_LOG_ERR
, "fuse_daemonize: setsid: %s\n",
308 nullfd
= open("/dev/null", O_RDWR
, 0);
310 rett
= dup2(nullfd
, 0);
314 rett
= dup2(nullfd
, 1);
318 rett
= dup2(nullfd
, 2);
327 /* Propagate completion of daemon initialization */
329 rett
= write(waiter
[1], &completed
, sizeof(completed
));
341 void fuse_apply_conn_info_opts(struct fuse_conn_info_opts
*opts
,
342 struct fuse_conn_info
*conn
)
344 if (opts
->set_max_write
) {
345 conn
->max_write
= opts
->max_write
;
347 if (opts
->set_max_background
) {
348 conn
->max_background
= opts
->max_background
;
350 if (opts
->set_congestion_threshold
) {
351 conn
->congestion_threshold
= opts
->congestion_threshold
;
353 if (opts
->set_time_gran
) {
354 conn
->time_gran
= opts
->time_gran
;
356 if (opts
->set_max_readahead
) {
357 conn
->max_readahead
= opts
->max_readahead
;
360 #define LL_ENABLE(cond, cap) \
363 #define LL_DISABLE(cond, cap) \
367 LL_ENABLE(opts
->splice_read
, FUSE_CAP_SPLICE_READ
);
368 LL_DISABLE(opts
->no_splice_read
, FUSE_CAP_SPLICE_READ
);
370 LL_ENABLE(opts
->splice_write
, FUSE_CAP_SPLICE_WRITE
);
371 LL_DISABLE(opts
->no_splice_write
, FUSE_CAP_SPLICE_WRITE
);
373 LL_ENABLE(opts
->splice_move
, FUSE_CAP_SPLICE_MOVE
);
374 LL_DISABLE(opts
->no_splice_move
, FUSE_CAP_SPLICE_MOVE
);
376 LL_ENABLE(opts
->auto_inval_data
, FUSE_CAP_AUTO_INVAL_DATA
);
377 LL_DISABLE(opts
->no_auto_inval_data
, FUSE_CAP_AUTO_INVAL_DATA
);
379 LL_DISABLE(opts
->no_readdirplus
, FUSE_CAP_READDIRPLUS
);
380 LL_DISABLE(opts
->no_readdirplus_auto
, FUSE_CAP_READDIRPLUS_AUTO
);
382 LL_ENABLE(opts
->async_dio
, FUSE_CAP_ASYNC_DIO
);
383 LL_DISABLE(opts
->no_async_dio
, FUSE_CAP_ASYNC_DIO
);
385 LL_ENABLE(opts
->writeback_cache
, FUSE_CAP_WRITEBACK_CACHE
);
386 LL_DISABLE(opts
->no_writeback_cache
, FUSE_CAP_WRITEBACK_CACHE
);
388 LL_ENABLE(opts
->async_read
, FUSE_CAP_ASYNC_READ
);
389 LL_DISABLE(opts
->sync_read
, FUSE_CAP_ASYNC_READ
);
391 LL_DISABLE(opts
->no_remote_posix_lock
, FUSE_CAP_POSIX_LOCKS
);
392 LL_DISABLE(opts
->no_remote_flock
, FUSE_CAP_FLOCK_LOCKS
);
395 struct fuse_conn_info_opts
*fuse_parse_conn_info_opts(struct fuse_args
*args
)
397 struct fuse_conn_info_opts
*opts
;
399 opts
= calloc(1, sizeof(struct fuse_conn_info_opts
));
401 fuse_log(FUSE_LOG_ERR
, "calloc failed\n");
404 if (fuse_opt_parse(args
, opts
, conn_info_opt_spec
, NULL
) == -1) {